UPDATE 04-04-15, Single Driver Experiments

[Marvel]

I agree that the phase plug is more critical for the compression drivers, and would think their use on DRs would be less so, as you have less high end to begin with. Agreed that looks sell products.

Have a great weekend.

[Klipschguy]

Neil,

A couple more thoughts on backloaders.

IMHO, the high frequency extension/smoothness is the toughest part about these single driver loudspeakers, especially when trying to balance it with the proclivity of fullrange drivers to have midrange "shoutiness." Without smooth treble, these speakers will be less than satisfying, read: dull. Whizzers are not a bad way to go, but without a whizzer, a small cone will tend to get the mid/high balance in better harmony than a larger full range cone. One can also add a tweeter, but that's cheating - right?

The low frequency extension will be largely controlled by the horn size, placement in the room, and the room itself. In other words a small driver will be able to produce bass based on the tuning of the horn - I know, I've heard it. A smallish sealed sub is not a bad way to round out the sound of these speakers, but not entirely necessary for good listening experience.

I really like the little FE83 - I wonder how they would perform in an array configuration in a backloaded horn?????????????????????????

Tell me a little about your listening experience with backloaders. I would really be interested to know (Neil, or anyone). These ideosyncratic, rather emperical speakers are interesting.

Andy

[DizRotus]

Andy-

As I type Im listening to American Routes through the drivers below:

PIONEER A11EC80-02F 4-1/2" FULL RANGE

Paper cone with treated cloth surround. Open back and stamped basket. Perfect for bookshelf type speakers and car stereo installations. * Power handling: 20 watts RMS/30 watts max * Voice coil diameter: 1" * Impedance: 8 ohms * Frequency response: 70-15,000 Hz * Magnet weight: 9.3 oz. * Fs: 70 Hz * SPL: 90 dB 1W/1m * Vas: .31 cu. ft. * Xmax: 1.1mm * Qms: 1.40 * Qes: .47 * Qts: .35 * Net weight: 2 lbs. * Manufacturer model number: A11EC80-02F * Dimensions: Overall Diameter: 4-1/2", Cutout Diameter: 4-1/8", Mounting Depth: 2-3/8", Magnet Diameter: 3-1/8", Magnet Height: 1".

The specs suggest that these should work as well in the rear horn as any of the five Im now using. They sound ok so far. On paper they compare to the Fostex FE83 and FE103. Ill try to get my hands on each of the Fostex drivers to test them in the enclosures.

I recognize the benefits of smaller drivers for the mid/high frequencies in rear horn enclosures. Nevertheless, if the benefits (read imaging) of the single driver rear horn configuration impress me sufficiently, I might build larger rear horn enclosures and experiment with 8 Fostex and/or AER full range drivers. I have absolutely no intention of resorting to tweeters or subwoofers. As you said, that would be cheating.

Edited November 15, 2013 by DizRotus

[DizRotus]

Semi-Promedia?

[DizRotus]

After more time listening to the various drivers and after more experimentation with stuffing the enclosures, the following can be said:

• 
  
• All of the drivers are benefitted by the back loading horn enclosures;
  
  
• All of the drivers sound respectable, or better, with respectable, or better, bass;
  
  
• My order of preference from best to worst is:
  
  1. 
     
  2. TB 656S;
     
     
  3. TB 616S;
     
     
  4. TB 654 S;
     
     
  5. Pioneer W-47-04 204; and
     
     
  6. Pioneer $0.39 driver (now $0.49).
  
  
  
  
• The differences from best to worst are not dramatic;
  
  
• The difference between the best and my Cornwalls is dramatic;
  
  
• The single drivers have better imaging than the Cornwalls;
  
  
• The Cornwalls have better highs and better bass; and
  
  
• The Cornwalls have a more effortless and open sound with much better dynamics.

The phrase preaching to the choir comes to mind when stating that Cornwalls are better for the reasons stated. That said, the single driver rear horn speakers sound better than many commercially made speakers costing much more. They’re at their best reproducing the intimacy of a jazz quartet. The string bass, piano, percussion and saxophone on Take Five on Brubeck’s Time Out are easily located left to right and front to back. I wish the Cornwalls could do the same as well. Female vocals and applause also sound very good.

Nevertheless, at their best, these drivers in the rear horn enclosures are no match for the Cornwalls. When time permits, I plan to try Fostex FE83 and/or FE103E drivers. While I will not be surprised if Fostex drivers sound better than the Tang Band 656S, I will be extremely surprised if the difference is substantial.

[PrestonTom]

Neil,

I have also been intrigued by the idea of single driver systems. I am glad to see that you are carrying through on this stuff. I assume that you already know that there are a bunch of websites with pertinent info. If not, try a google search. I know you will find it very helpful. Keep us informed. I agree that is amazing how a proper cabinet/design can bring out the best in a modestly priced transducer. I suspect you are having a blast learning about this stuff also.

Good luck,

-Tom

[DizRotus]

Tom-

I've visited the following, among others:

http://melhuish.org/audio/horn.html

http://www3.ocn.ne.jp/~hanbei/eng-links.html

http://www.atatan.com/~s-ito/sp/makizou.html

http://www.plasmatweeter.de/jericho.htm

If you have links to other pertinent sites, I'd like to see them.

[mike stehr]

Dunno if I could live with a back loaded horn with such small drivers...but it look's like a fun project nonetheless.

I like the way you can swap baffles.

Adire makes a cool little 4 incher that has a copper phase plug, though they meant for bass reflex I think and are spendy. $130 a pair?

If you can live with bass reflex or sealed, a larger driver will get you more bass.

I'm using a 12" Utah/Realistic "Americana" with the cone tweeters unhooked, sealed in a 3 and half foot cabinets running full-range.

Roll-off is at around 45 Hz, though they sure sound like they go lower.

The Utah/RS driver with cone tweeters unhooked cruises up to 10,500 Hz before roll-off. A selenium 8 ohm slot tweeter capped off with a 2 uF Cornell dublier oil cap and a L-pad add the air on top.

The bass response while not as sensitive as my '83 Cornwalls, it's tighter with less boom, and can go as loud no problem.

The mid and top end seems just a little more coherant on most recordings. JMHO, WTFDIK, etc....

I dunno, they are two different speakers, that's for sure.

[Klipschguy]

Neil,

What you are hearing with these backloaders is my general experience as well (I also have Cornwalls as my "reference"). Cornwalls are real tough to beat - for any speaker. I love your setup to test different drivers. Please keep us posted on your experiments. Interesting.

Jazz is good on backloaders, real good. Rock, especially on vinyl, is unsatifying. Classical is quite good. Hammered dulcimer is unbelievable. Classical and acoustic guitars are excellent.

As stated earlier, lighter cones tend to sound more dynamic.

The thing that is most impressive about these backloaders is that you tend to find yourself listening to the music rather than the speakers, which is really what it's all about. I cannot really explain it, but it is a good thing.

I would not recommend a DIY backloader for your primary system, but they have their place.

Andy

[sunnysal]

I too enjoyed my experiments with my single driver (a fostex FE208sigma), I tried backloaded and reflex cabs with it. After a while I gravitated back to my heritage speakers. I guess I need the slam and extension since I listen to a lot of rock. Regards, Tony

[DizRotus]

Thank you Andy aka Klipschguy. The Radio Shack FE103s arrived today (the USPS owes you a refund for Priority delivery). The attached photo shows one in place. My early opinion is that they sound as good as, if not better than, any of the others tried to date. But, theres a saying in the DIY speaker world that the best sounding speakers are the ones you just built.

Ive yet to perform any blind comparisons, but Ive been using the Pioneer W-47-04 204 drivers for several days. To be able to listen to the new free speakers quickly, I removed the Pioneer 49 cent drivers from their motor boards and installed the RS FE103s. While listening to FM jazz I swapped the first RS FE103 for the Pioneer on the fly. My initial impression was that the FE103 played slightly louder, but with less bass.

I next listened to Take Five from Brubecks Time Out CD. That was followed by several cuts from Diana Kralls Live In Paris CD. The speakers sound VERY good. The imaging is better than the other single drivers, which are better than the Cornwalls. At the risk of speaking like an audiophool, the detail seems more palpable. The percussion is crisper, the piano and vocals more natural and applause sounds like applause, rather than rain.

Naturally, all of the foregoing is a subjective assessment based on a brief listen. When time permits, Ill enlist my 15 year-old son to switch among the various drivers so that I can try to blindly distinguish one from another and pick a favorite, without any unintentional bias.

Thank you again Andy. I wish you could hear them. Next time you get to <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />BirminghamMichigan, not Alabamalet me know.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

[Klipschguy]

Hi Neil,

Your welcome! It was my pleasure to send them to you. Thank you for the pictures and listening impressions. If I'm in Michigan, we'll have to arrange a listening session!

Andy

[DizRotus]

Still no blind comparison, but, after more listening time, the RS FE103s still seem to sound better than the other drivers.

Does anyone know what the cost of these was at Radio Shack? I'm guessing in the neighborhood of $5.00 each. Also, does anyone know when these were discontinued by Radio Shack?

The surrounds on these are concave, instead of the more typical convex. Does anyone know the reason, significance and/or impact of this design anomaly?

[DizRotus]

My subjective impression is that the RS 40-1197s clearly sound better than the rest of the drivers, especially the highs.

Nevertheless, in very limited blind comparisons, I was unable to distinguish between the RS 40-1197s and the Pioneers (not the 49 centers). Oh bother.

[DizRotus]

I really like the sound of the RS 40-1197s. Now I'm tempted to modify them as described in a few DIY sites. If I could score another pair I'd chance it, but I don't want to risk the two that were so generously provided by Klipschguy.

I'd be interested in hearing about any other single driver rear horn projects that any forum members have conducted.

Craig, I should bring these up to see how they sound when powered by VRDs?

[TBrennan]

A little history on backhorns and their reason for being is in order.

It all goes back to Voight who developed the Lowther drivers back in the 30s. Voight had the notion that the best direct-radiator would have the lightest possible cone and the most powerful possible motor. This makes sense on the face of it but it resulted in an overdamped driver that made very strong mids and very poor bass.

Voight hit on the idea of rear hornloading to bring at least some of the bass up to the level of the direct-radiating midrange. I call this horn loading in self defense.

Now I've heard many rear horns using wide-range drivers such as Lowthers and Fostex and NONE of them made very good bass. If one is enthralled with the idea of using wide-range drivers it's much easier to use the driver in a box or open baffle and use a sub for the bass. Doing this you not only save on complex cabinetry but you also get much better bass.

Note too that most of the backhorns used with wide-range drivers are woefully undersized with short paths and mouths not as big as those on Altec midrange multicell horns. The result is often the effect of a poorly tuned pipe with many dips and peaks. I recall Tom Danley (or was it Bruce Edgar? They were both at the meeting) showing our Chicago Horn Club response graphs of small rearhorns that looked like roller-coasters.

In short I think rear horn-loading of this class of drivers is a waste of time and wood. The best implementations of wide-range drivers I've heard are Kurt's Fostex FX-200s in open baffles with subs and Mats' Supravoxes in open baffles with subs.

Mats has since become enthralled with Altecs.

One of our club members has excellent sounding Lowther-Medallions. But he EQs the Lowthers and uses a.....sub.

[sunnysal]

I agree with Tom, after playing around with a bunch of cabinets in which to utilize my Fostex 8" FE208sigmas I say let the wide range drivers do what they do best, a broad midrange that sounds great, and complement them with a sub and possibly a tweeter (I can run my speakers from about 200hz to about 12khz with success in an open baffle).

I have to recommend two 4.5" drivers from fostex that amazed me, the FX120 and F120a both had extension down to 50hz and made it almost up to 20khz, very smooth response curves and they sounded great. they are the closest I have found to real full range sound from a single driver, in a bass reflex enclosure they sounded GREAT. you cannot expect one 4.5" driver to fill a big room, but if you take into consideration output limitations they are the best I have heard. (and the FX120 was under $200 for the pair!).

regards, tony

[Klipschguy]

Neil, I'm glad you're enjoying the drivers. It is however interesting the sub-dollar pioneers do about as good a job!

Tom, interesting reply. I agree that good bass is tough to get out of a backloader - and the response is lumpy. However, careful room positioning can compensate for some of the deficiencies.

Backloaders are no match for something like Cornwalls (which Neil also owns), but they are not without their charm - especially with jazz and acoustic music. I like the imaging and midrange clarity.

Albeit backloaders are ideosyncratic, a "waste of wood" is a bit of an overstatment; it may apply to some (many) backloaded designs, but certainly not ALL - just like saying all horn speakers are "shouty and only suitable for PA and commercial applications" is an overstatement.

Have you ever heard a backloaded horn that you thought sounded decent?

Andy

[sunnysal]

andy, I guess you were asking Tom BUT the best cabinet I heard with a full range was the "basszilla" by dick olsher, his had the "full" range driver (a fostex or lowther either could be used) in an open baffle that sat on top of a carefully designed sub woofer section, that was the best I ever heard.

Based on what I heard I bought the plans and some parts but have never assembled it, mainly because the bass drivers were SO expensive! dick put in a lot of effort to find a woofer that matched well with the siingle driver.

every backhorn I have built or heard was exptremely flawed...not so much so that they were awful to listen to but when I compared them with my klipschorns or other good multi driver speakers it highlighted the limited or varied response curve.

warm regards, tony

[DizRotus]

----------------

On 7/27/2005 2:34:27 AM TBrennan wrote:

In short I think rear horn-loading of this class of drivers is a waste of time and wood.

----------------

Tom-

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

I respect your experience and dont disagree with what you said except the last part quoted above.

How can a DIY horn person call this experiment, a waste of time (recreation) and wood (free available underlayment)?

Its a hobby, not a business.

The enjoyment for me is in the process as much as the result.

I enjoy the pleasure of watching the reactions from people who cant believe theyre listening to 4 Radio Shack speakers in homemade particle board enclosures; total cost $0.00, instead of the giant Klipsch Cornwalls.